Global Upper Ocean Thermohaline Parameters from World Ocean Atlas 2018

Seventeen derived parameters, including mixed layer depth and barrier layer depth, characterize the upper ocean's thermal and saline structure. The dataset is derived from the NOAA National Centers for Environmental Information's World Ocean Atlas 2018 climatology, processed using an exponential leap-forward gradient method. Data are provided on 0.25-degree and 1-degree global grids for each calendar month.

Use Cases

• Analyzing seasonal variation in mixed layer depth (MLD) and isothermal layer depth (ILD) across global 0.25-degree grids.
• Investigating barrier layer presence and strength by calculating ILD minus MLD differences.
• Estimating upper ocean heat content using the ITL heat content parameter for climate studies.
• Correlating mixed layer fresh-water content with regional precipitation or evaporation patterns.
• Mapping thermocline and pycnocline gradients to identify oceanic frontal zones and water mass boundaries.

Strengths

• Provides 17 distinct derived thermohaline parameters for comprehensive upper ocean analysis.
• Includes data quality flags via an I-index, with values below 0.5 flagged for user awareness.
• Offers two spatial resolutions (1-degree and 0.25-degree grids) for different analysis scales.

Limitations

• Based on a 2018 climatology, so it does not capture recent oceanographic changes or interannual variability after that period.
• Data flagged with an I-index < 0.5 are excluded, which may create gaps in certain regions or conditions.
• As a derived climatological product, it represents long-term averages rather than real-time or synoptic conditions.

Provenance

Source

NOAA National Centers for Environmental Information (NCEI) World Ocean Atlas 2018.

Collection Method

Parameters derived from climatological gridded vertical profiles using an exponential leap-forward gradient method.

Time Range

Climatological period (long-term average), specific years not stated.

Freshness

Climatological data derived from World Ocean Atlas 2018, with a last updated date of 2017-12-31.

Geography

Global ocean coverage.